Technical Field
This disclosure is directed to electronic systems having integrated circuits, and more particularly, to signal transmission in and between integrated circuits.
Description of the Related Art
As the speed at which integrated circuits operate has increased, there has been a corresponding increase in the challenges of signaling. In particular, ensuring signal integrity, and thus data integrity, is a critical factor in any successful integrated circuit design, as well as for any electronic system in which signals are transmitted from one integrated circuit to another.
Speed and distance are two related factors to be considered in determining a signaling strategy. At longer distances, signals may degrade over time, adversely affecting the ability of a receiver to correctly interpret the data contained therein. Factors such as resistance in the transmission paths may cause degradation of signals in flight. Process, voltage, and temperature variations can also be factors in signal degradation. Moreover, as clock speeds increase, distance becomes more of a challenge. This is due to smaller time windows at which signals must arrive at their respective destinations.
In some cases, devices such as repeaters may be placed in a signal path between a transmitter and receiver. Such repeaters may provide strength to signals that may otherwise degrade in transmission. Another signaling technique is to use source synchronous signaling, in which a clock signal is transmitted along with the data signals.